Free Percentage Calculator Online
Five percentage calculators in one. Instant results as you type.
Key Features
Everything you need in one free tool
Covers all common percentage calculations: percent of, what percent, change, add, and subtract.
Results update in real time as you type. No button press required.
Runs entirely in your browser with no downloads or accounts needed.
About This Tool
A percentage expresses a part of a whole in hundredths, so 25% means 25 out of every 100. This calculator handles the three questions people run into most: what a percentage of a number is, what one number is as a percentage of another, and the percentage change between two values.
The math is straightforward once the roles are clear. To find a percentage of a value you multiply by the rate divided by 100; to express a ratio as a percentage you divide the part by the whole and multiply by 100; and percentage increase or decrease is the difference divided by the original value. Doing it here removes the rounding mistakes that creep in when you juggle decimal points by hand.
A frequent mistake is treating a percentage increase and the matching decrease as reversible: a value that rises 50% and then falls 50% does not return to where it started, because the second percentage applies to the larger figure. Working each step through the tool avoids that trap.
How to Use It
- Pick the calculation you need: percent of a number, a ratio as a percent, or the change between two numbers.
- Type the two known values into the fields.
- Read the result instantly, with the underlying formula shown so you can check the working.
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